TY - JOUR
T1 - Millimetre-wave emission from an intermediate-mass black hole candidate in the Milky Way
AU - Oka, Tomoharu
AU - Tsujimoto, Shiho
AU - Iwata, Yuhei
AU - Nomura, Mariko
AU - Takekawa, Shunya
N1 - Funding Information:
This paper makes use of the following ALMA data: ADS/JAO.ALMA#2011.0.01234.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. We thank the ALMA staff for the operation of the array and delivering the qualified data. We also thank S. Nakashima and M. Nobukawa for calculating the upper limit to the X-ray flux, and A. E. Higuchi for helping in ALMA data reduction with CASA. T.O. acknowledges support from JSPS Grant-in-Aid for Scientific Research (B) No. 15H03643.
Publisher Copyright:
© 2017 The Author(s).
PY - 2017/7/1
Y1 - 2017/7/1
N2 - It is widely accepted that black holes with masses greater than a million solar masses (M ·) lurk at the centres of massive galaxies. The origins of such 'supermassive' black holes (SMBHs) remain unknown 1, although those of stellar-mass black holes are well understood. One possible scenario is that intermediate-mass black holes (IMBHs), which are formed by the runaway coalescence of stars in young compact star clusters 2, merge at the centre of a galaxy to form a SMBH 3. Although many candidates for IMBHs have been proposed, none is accepted as definitive. Recently, we discovered a peculiar molecular cloud, CO-0.40-0.22, with an extremely broad velocity width, near the centre of our Milky Way galaxy. Based on the careful analysis of gas kinematics, we concluded that a compact object with a mass of about 105 M · is lurking in this cloud 4. Here we report the detection of a point-like continuum source as well as a compact gas clump near the centre of CO-0.40-0.22. This point-like continuum source (CO-0.40-0.22∗) has a wide-band spectrum consistent with 1/500 of the Galactic SMBH (Sgr A∗) in luminosity. Numerical simulations around a point-like massive object reproduce the kinematics of dense molecular gas well, which suggests that CO-0.40-0.22∗is one of the most promising candidates for an intermediate-mass black hole.
AB - It is widely accepted that black holes with masses greater than a million solar masses (M ·) lurk at the centres of massive galaxies. The origins of such 'supermassive' black holes (SMBHs) remain unknown 1, although those of stellar-mass black holes are well understood. One possible scenario is that intermediate-mass black holes (IMBHs), which are formed by the runaway coalescence of stars in young compact star clusters 2, merge at the centre of a galaxy to form a SMBH 3. Although many candidates for IMBHs have been proposed, none is accepted as definitive. Recently, we discovered a peculiar molecular cloud, CO-0.40-0.22, with an extremely broad velocity width, near the centre of our Milky Way galaxy. Based on the careful analysis of gas kinematics, we concluded that a compact object with a mass of about 105 M · is lurking in this cloud 4. Here we report the detection of a point-like continuum source as well as a compact gas clump near the centre of CO-0.40-0.22. This point-like continuum source (CO-0.40-0.22∗) has a wide-band spectrum consistent with 1/500 of the Galactic SMBH (Sgr A∗) in luminosity. Numerical simulations around a point-like massive object reproduce the kinematics of dense molecular gas well, which suggests that CO-0.40-0.22∗is one of the most promising candidates for an intermediate-mass black hole.
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U2 - 10.1038/s41550-017-0224-z
DO - 10.1038/s41550-017-0224-z
M3 - Article
AN - SCOPUS:85037083640
SN - 2397-3366
VL - 1
SP - 709
EP - 712
JO - Nature Astronomy
JF - Nature Astronomy
IS - 10
ER -